1. Field of the Invention
The invention relates to amphiphilic compounds with at least two hydrophilic and at least two hydrophobic groups based on dicarboxylic diesters.
2. Description of the Background
A wide variety of anionic, cationic, nonionic and zwitterionic compounds are known as amphiphilic substances. By far the most of these substances consist of a hydrophilic head group and at least one hydrophobic part.
With the amphiphilic substances there is a need, for ecological reasons, for example concerning the reduction in the cost of packaging and transport, to achieve an increasingly greater effect per mass of substance employed. Since optimization by mixing amphiphilic substances produces only very limited advances, novel amphiphilic substances with greater efficiency are required. It is therefore necessary in particular to find substances with lower critical micelle concentrations and/or lower surface and interfacial tensions in order to be able to reduce markedly the amounts of active substance used.
Initial approaches to a solution in this direction by doubling one part of the structure (hydrophilic head group, hydrophobic group) have already been disclosed. Thus, cationic surface-active compounds can be obtained by adding long-chain alkyl halides onto permethylated alkylenediamines [R. Zana, M. Benrraou, R. Rueff, Langmuir, 7 (1991) 1072: R. Zana, Y. Talmon, Nature, 362 (1993) 228; E. Alami, G. Beinert, P. Marie, R. Zana, Langmuir, 9 (1993) 1465].
Anionic surface-active compounds with at least two hydrophilic and at least two hydrophobic groups have to date been prepared only on the basis of diglycidyl ethers (U.S. Pat. No. 5,160,450, JP 01 304 033, JP 4 124 165). However, diglycidyl ethers are regarded as toxicologically objectionable and are rather costly. Furthermore, epichlorohydrin is used for their preparation, which leads to large amounts of residues so that these compounds are no longer in accord with the times from the ecotoxicological and economic viewpoints.